Growth and Transpiration of Jatropha curcas L. Seedlings under Natural Atmospheric Vapour Pressure Deficit and Progressive Soil Drying in Semi-Arid Climate

Abstract

During the last decade, Jatropha curcas L. (J. curcas) has gained much attention worldwide as biofuel crop. Although its cultivation is promoted in the Sahel, there is a surprising lack of data on its water use regulation and growth in this region. Here, we investigated, in semi-controlled conditions, leaf transpiration and growth of six accessions of J. curcas at seedling stage under natural changing in vapour pressure deficit (VPD) and progressive soil drying in Senegal. The experimental layout was a randomized complete bloc design and after 3 months of growth arranged to a split-plot at the implementation of water stress to facilitate irrigation. Under well water condition, there was no significant difference between accessions for leave transpiration that was positively correlated to VPD with high values recorded between 13 h and 14 h pm. Accessions of J. curcas used in this study showed closed thresholds at which transpiration declined except accession from Ndawene that threshold was lower (0.30). There is no significant difference between accessions for growth during the experimentation period. In 3 months, we recorded 23.57 g for the aboveground dry biomass and seedlings had about 14 leaves and 24.3 cm height. Positive linear correlation was recorded between aboveground biomass and root dry weight (p < 0.0001) and between total biomass and collar diameter (p < 0.0001) as well as between leaf area and leaf dry weight (p < 0.0001). In natural climatic conditions in Sahel zone, cultivation of J. curcas might need complement irrigation for a better growth of seedlings especially during the dry season.